All Kufr (Disbelief) is one religion and the kuffaar (disbelievers) are one nation. Allah Ta'ala says (the meaning): "As for the disbelievers, they are guardians of one another. And unless you ˹believers˺ act likewise, there will be great oppression and corruption in the land." (al-Anfal 73) Allah has decreed there to be two camps of mankind and jinnkind in this dunya: The party of God and the party of Satan. The followers of Truth and the followers of falsehoods. Those on the straight path and those on the deviant paths. And this has been true since the days of Habil and Qabil and it's true to this day. Whatever numerous other paths exist besides the Straight Path of Islam: All of them are the same path, because they all lead to the same destination (the Fire). The Kuffaar will always unite and conspire against the Muslims, and they will do this even if they have diametrically opposed ideologies. The most succinct example of this being the way Jews and Christians are uniting in love and support of one another, even though the Jews hate and reject Jesus (a.s), whom the Christians claim to love. If they do love him, why are they siding with a people who hates him against a people who also loves him? It's because all the kuffaar are one nation. All of the Kuffaar are one nation who help and support each other against Islam, whether they are Jews, Christians, Atheists, Buddhists, Hindus or whoever else. Therefore, the Muslims must likewise become one nation in support of each other and in support of the truth. And therefore, the Muslims must not become allies of the Kuffaar against other Muslims. And unless this is fulfilled, "there will be great oppression and corruption in the land" as the verse says, and we see this happening today.